Family Solanaceae
Datura stramonium, known by the common names Jimson weed or datura is a plant in the Solanaceae (nightshade) family, which is believed to have originated in the Americas, but is now found around the world. 
All parts of Datura plants contain dangerous levels of the tropane alkaloids atropine, hyoscyamine and scopolamine which are classified as deliriants, or anticholinergics. There is a high risk of fatal overdose amongst uninformed users, and many hospitalizations occur amongst recreational users who ingest the plant for its psychoactive effects. The amount of toxins varies widely from plant to plant. There can be as much as a 5:1 variation across plants, and a given plant's toxicity depends on its age, where it is growing, and the local weather conditions. Additionally, within a given datura plant, concentrations of toxins are higher in certain parts of the plant than others, and can vary from leaf to leaf. When the plant is younger, the ratio of scopolamine to atropine is approximately 3:1; after flowering, this ratio is reversed, with the amount of scopolamine continuing to decrease as the plant gets older. This variation makes Datura exceptionally hazardous as a drug. In traditional cultures, a great deal of experience with and detailed knowledge of Datura was critical in order to minimize harm. An individual datura seed contains about 0.1 mg of atropine, and the approximate fatal dose for adult humans is >10 mg atropine or >2–4 mg scopolamine.
Datura intoxication typically produces delirium (as contrasted to hallucination); hyperthermia; tachycardia; bizarre behavior; and severe mydriasis with resultant painful photophobia that can last several days. Pronounced amnesia is another commonly reported effect. The onset of symptoms generally occurs approximately 30 minutes to an hour after smoking the herb. These symptoms generally last from 24 to 48 hours, but have been reported in some cases to last as long as 2 weeks.
As with other cases of anticholinergic poisoning, intravenous physostigmine can be administered in severe cases as an antidote.
Datura has long been used as an extremely effective treatment for asthma symptoms. The active anti-asthmatic agent is atropine, which causes paralysis of the pulmonary branches of the lungs, eliminating the spasms that cause the asthma attacks. The leaves are generally smoked either in a cigarette or a pipe. This practice of smoking datura to relieve asthma has its origins in traditional Ayurvedic medicine in India. After this was discovered during the late 18th century by James Anderson, the English Physician-General of the East India Company, the practice quickly became popular in Europe.
The Zuni used to use datura as an analgesic, to render patients unconscious while broken bones were set. The Chinese also used it in this manner, as a form of anaesthesia during surgery.
Atropine and scopalamine (both of which are found in very high concentrations in datura) are muscarinic antagonists which can be used to treat Parkinson's disease and motion sickness, and to inhibit parasympathetic stimulation of the urinary tract, respiratory tract, GI tract, heart and eye.
Datura can be used to assist in the process of breaking drug addictions, by reducing the symptoms of delirium tremens and morphine withdrawals.
Other medicinal uses for datura include providing relief from sore throat or toothache and getting rid of parasites.
Datura should be avoided by patients with heart problems, glaucoma, enlarged prostate, urinary difficulties, fluid buildup in the lungs, or bowel obstructions.
